Self-locking safety snatch block



Nov. 15, 1955 F, B RK ET AL 2,723,834

SELF-LOCKING SAFETY SNATCH BLOCK Filed March 6, 1955 I9 is 43 25 2/ I6 INVENTORS FEEDER/CK C. BURKE AND ALBERT F ATK/NS BY Z 4 W2- W United States Patent SELF-LOCKING SAFETY SNATCH BLOCK Frederick C. Burke, San Diego, and Albert E. Atkins, El Cajon, Calif.

Application March 6, 1953, Serial No. 340,936

9 Claims. (Cl. 254193) (Granted under Title 35, U. S. Code (1952), sec. 266) line. coming adrift under any conditions of use of the block.

Snatch blocks of this type heretofore devised and used generally have provided for insertion of the block into the line as by the provision of relatively movable sheave checks which support the pin upon which the sheave or pulley is journalled, one cheek being rotated about the pivot pin relative to the other to provide an opening into the block to permit placing of the line on the sheave without threading through the block. Such block arrangements have not been found to be entirely satisfactory in service for the reason that the blocks must be manually closed and then locked, usually by some intricate mechanism. The technical reason for this functional shortcoming of the prior art devices is that there is no natural or directed force on such a block tending to close the same and hold it in closed position.

According to the arrangement of the present invention, a swivel eye to which the hauling line is connected, is pivotally secured to a U-shaped strap which, in turn, is pivotally secured in the swallow of the block by pivotal connection to one of the cheeks at a peripheral extension thereof. The other lag of the U-shaped strap is extended into face adjacency with the other cheek and slotted at its extremity to engage the sheave journal pin, the arrangement thus being such that tension on the hauling line accompanied by tension on the line on the sheave automatically causes the strap extension to pivot in a direction 'to engage the sheave pivot pin whereby the block is closed and remains closed as long as there is tension in the lines.

An object of the present invention is to provide a selfclosing snatch block.

Another object and important feature of the present invention resides in the provision of a new and improved snatch block having provision for quick opening thereof .and for self-closing of the block in response to tension .in the lines.

this invention will be readily appreciated as the same becomes better understood by reference to the following .detailed description when considered in connection with .the accompanying drawings wherein:

Fig. 1 is a view in side elevation of a snatch block according to the preferred embodiment of the present invention, certain parts being broken away to illustrate details of construction and certain parts being shown in solid and in dashed line positions to illustrate details of operation; Fig. 2 is a view in elevation of the snatch block of Fig. 1 as viewed from the left in Fig. 1; Fig. 3 is a fragmentary sectional view taken along the line 3-3 of Fig. 1; Fig. 4 is a side elevational view of a multisheave arrangement of the snatch block of the present invention; Fig. 5 is a view in elevation of the snatch block of Fig. 4 as viewed from the left in Fig. 4; Fig. 6 is a fragmentary sectional view of the snatch block as seen along the line 66 of Fig. 4; and Fig. 7 is a fragmentary view in elevation of the snatch block as viewed along the line 7-7 of Fig. 5 when the strap of the block has been moved to cable receiving position.

Referring now to the drawings where like characters of reference refer to like parts throughout the several views, the hauling line (not shown) is secured in any well known manner to the swivel eye 10, the shank 11 of which is freely received, in each case, within an opening provided therefor in the bight of U-shaped straps 12 and 12A respectively, the swivel being held in position for free pivotal movement on the strap by the collar 13 which is secured to the shank as by the pin 14.

Strap 12 has a short leg 15 and an elongated leg 16 which carry a pivot pin 17, the pin 17 being secured against movement relative to the legs as by the pin 18.

Pivot pin 17 is journalled in a suitable opening provided therefor in a peripheral extension 19 of a check 21. The central threaded opening 22 of cheek 21 carries a shoulder screw 23 which, in turn, supports a roller bearing 24 and a second cheek 25. A sheave 26 is rotatively carried by bearing 24 which, in turn, is supported on a sleeve 30 which serves as a spacer to provide adequate clearance between the cheeks for rotary movement of the sheave therebetween. Obviously, sleeve 30 may be formed integrally with shaft 23 or may comprise the inner race of bearing 24 when this is desired. The inner faces of the cheeks preferably are undercut as at 27 and 28 respectively so that the circumferential shoulders 29 and 31 thereby provided overhang the sheave and thus prevent working of the line between the sheave and the cheeks. Relative rotation of checks 21 and 25 about screw 23 is prevented by a second screw 32 which is carried by peripheral extensions 33 and 34 of cheeks 21 and 25 respectively. A spacer 35 carried by screw 32 intermediate the extensions 33 and 34 provides the proper spacing between the cheeks and maintain the same in rigid spaced relation upon tightening of the nut 36 on screw 32.

Shoulder screw 23, as shown, is threaded at its extremities, the larger diameter extremity being threadedly received by cheek 21 and locked in position therein by a nut 40, the desired position being as shown wherein the shoulder provided by the reduced extremity of screw 23 is flush with the outer face of cheek 25.

The elongated leg 16 of strap 12 is slotted as at 37 to receive the reduced extremity of screw 23, as may best be seen in Fig. 3, when the strap has been pivoted from the dashed position of Fig. 1 to the full-line position illustrated in Figs. 1 and 2. The strap may be locked in this position by tightening wing nut 38 against washer 39. However, as will appear more fully hereinafter, the natural tendency of the block in use is to retain the strap in closed position.

Pivot pin 17 carries a tongue member 41 to which it is secured for pivotal movement as by the pin 42 within the swallow of the block. Tongue member 41 is generally of cylindrical configuration and serves as a spacer for maintaining the legs of the strap 12 in adequate spaced relation with respect to cheeks 21 and 25 for free pivotal movement relative thereto. Tongue member 41 has a peripheral extension 43 on tongue portion proper, which, as may be seen in each of Figs. 1 to 3, extends between the cheeks 21, and just inwardly of the circumferential outlines thereof to close the block whereby a line when wound about the sheave 26 cannot be removed therefrom over the cheek 25 as at 44, Fig. 2.

It will be noted from Fig. 2 that the axis of shank 11 extends midway between cheeks 21 and 25, and in Fig. 1 it will be noted that the axis of the shank intersects the axis of the strap pivot pin 17 which defines a common plane with the axis of shoulder screw 23. Thus, by reason of this arrangement, any pull on swivel 10, accompanied by oppositely directed tension on sheave 26 when strap 12 is in the block open position, as illustrated by the dashed lines of Fig. 1, results in a natural tendency of the strap to pivot until the axis of the swivel shank 11 intersects the axis of shoulder screw 23, in which position the notch 37 in the strap moves to receive the screw and the block is closed by reason of the position thus assumed by the tongue 43 between the cheeks, as aforedescribed.

To open the block to remove the line from the sheave, it merely is necessary to tilt the strap to the dashed line position of Fig. 1, wing nut 38 being loosened, if necessary. When the strap is tilted, tongue 43 is rotated therewith and thus is withdrawn from between the cheeks, leaving a clear passage between the opening 45, which becomes enlarged, and the peripheral area 46 surrounding the sheave, through which passage the line may be withdrawn from the block.

The multiple sheave block disclosed in Figs. 4 to 7 comprises two sheaves 26A and 263 but is otherwise con structed similarly and operates in generally the same manner as the block disclosed in Figs. l to 3. The multiple sheave block may be pictured as a single sheave block with the sheave 26 and cheek 25 of Fig. 2 duplicated on the left side of cheek 21, as viewed in Fig. 2. The two sheaves thus have a common centrally disposed check 47, similar to cheek 21, which preferably makes a close fit with the sleeve A, Fig. 6. This sleeve, which may be formed integrally with shaft 23A, supports the sheave bearings 24A and 248. Both extremities of shaft 23A are threaded and formed similarly to the reduced extremity of shaft 23, one end being identical therewith and carries a wing nut 33 and washer 39. The other extremity carries a nut A.

The outer cheeks 25A and 25B are similar to cheek 2S and have central openings through which the extremities of shaft 23A extend. The extensions 34 of cheeks 25A and 25B carry a screw upon which are sleeved a pair of spacers 35, these being respectively interposed between the common cheek 47 and the two outer cheeks 25A and 25B, the cheeks thus being held in rigid spaced relation when the nut 36A is tightened on screw 32A. The peripheral extension 48 of cheek 47 extends beyond the extensions 34 of cheeks 25A and 25B and is provided with an opening 49 for facilitating handling of the block.

In the multiple sheave arrangement, it will be noted that the strap 12A is widened at the bight and has two elongated legs 16A and 163 which may be identical to leg 16 of strap 12 and which are similarly notched as at 37 to receive the extremities respectively of shaft 23A. The pivot pin 17A of this strap is journalled in the extension 51 of common cheek 47 and is secured to leg 16A by pin 18A. A pair of tongue members 41 individual to sheaves 26A and 26B are secured to pin 18A for pivotal movement therewith as by pins 42 and perform the same functions with respect to the sheaves and cheeks individual thereto as heretofore described in connection with sheave 26, check 25 and the tongue member 41 associated therewith.

From the foregoing the block opening and closing operations of the multiple sheave block should now be apparent. Suffice it to state that upon pivotal movement of strap 12A, to a position illustrated in Fig. 7 wherein the legs 16A and 16B are substantially tangential to the 4 cheeks 25A and 255, both tongues 43 pivot outwardly from between the cheeks individual thereto and respectively form openings through which the lines individual to sheaves 26A and 2633 may be removed over the peripheral edges of cheeks 25A and 25B. A pull on swivel 10 automatically tilts strap 12A to close the block in the same manner heretofore described in connection with the closing movement of strap 12 of the single sheave block.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Having described the invention, what is claimed is:

l. A self-closing snatch block for use with a hauling line comprising a sheave, a pair of cheeks for the sheave, means for securing the cheeks against relative rotation with respect to each other, means pivotally connected to one of the checks for pivotal movement about a pivot axis parallel to the axis of rotation of said sheave and including means for securing the hauling line to the block, and means carried by said pivotally connected means and pivotal therewith about said pivot axis within the swallow of the block for closing the block in response to a pull on said hauling line.

2. A self-closing snatch block for use with a hauling line comprising a sheave, a pair of cheeks having means for journalling said sheave in spaced relation therebetween and having additional spacing means for preventing relative rotation of the cheeks with respect to each other, means pivotally connected to one of said checks for pivotal movement about a pivot axis parallel to the axis of rotation of said sheave and arranged with respect to the cheeks in a manner forming the swallow of the block therewith, means secured to said pivotally connected means for attaching the hauling line to the block, and tongue means disposed within said swallow of the block and connected to said pivotally connected means for pivotal movement therewith about said pivot axis in response to a pull on said line, said tongue means having a tongue portion which moves into a position between said cheeks and adjacent the peripheral surface of said sheave thereby to lock the block as said tongue means pivots in response to said pull on the line.

3. A self closing snatch block for use with a hauling line comprising a pair of rigidly spaced and relatively non-rotatable cheeks, a sheave journalled therebetween, block closing means pivotally connected to one of the cheeks for pivotal movement about a pivot axis parallel to the axis of rotation of said sheave and including a tongue carried thereby for pivotal movement about said pivot axis into a position between the cheeks and adjacent the peripheral surface of the sheave, and means connected to said closing means for securing said hauling line to the block, said line securing means being disposed in spaced relation from the pivot axis of said tongue whereby the closing means is pivoted into said position thereof in response to a pull on said hauling line.

4. A self closing snatch block for use with a hauling line comprising a pair of rigidly spaced and relatively nonrotatable circular cheeks, a shaft carried by said cheeks concentrically thereof, a sheave rotatively supported on said shaft between the cheeks, block closing means having a pivotal connection with one of said cheeks for pivotal movement about a pivot axis parallel to the axis of rotation of said sheave and having a first extension engageable with said shaft and a second extension disposed to the opposite side of said pivotal connection from said first extension, means secured to said second extension for attaching said hauling line to the block, said closing means being pivoted to bring said first extension into engagement with said shaft in response to a pull on said line, and a tongue secured to said closing means for pivotal movement therewith about said pivot axis, said tongue being arranged to move into a position between said cheeks and adjacent the peripheral surface of the sheave as said first extension moves to engage the shaft thereby to lock the block.

5. A snatch block as in claim 4 further characterized by means carried by the shaft and engageable with the first extension for locking the closing means in the closed position of the block.

6. A self closing snatch block comprising a pair of circular cheeks having a journal pin and a sheave rotatively supported on said pin between the cheeks, one of said cheeks having a peripheral extension, a U-shaped strap having one of the legs thereof pivotally secured to said extension for unitary pivotal movement of the strap about an axis parallel to said pin and having the other one of the legs extended from the pivot axis into face adjacency with the other cheek, said extended leg having the extremity thereof slotted to receive said journal pin, and a swivel eye pivotally secured to the bight portion of said strap.

7. A snatch block as in claim 6 and having a tongue disposed within the swallow of the block secured to the strap for pivotal movement therewith about said pivot axis, said tongue being movable into a position between the cheeks and adjacent the peripheral surface of the sheave as said extended leg of the strap moves to engage the journal pin.

8. A self closing snatch block comprising a pair of circular cheeks, a sheave, means including a shaft disposed concentrically of the checks for rotatively supporting the sheave in predetermined spaced relation therebetween, a pair of peripheral extensions on said cheeks, respectively, means including a spacer interposed between said cheek extensions for maintaining the cheeks rigidly in said predetermined spaced relation, a second peripheral extension on one of said cheeks in diametrically opposed relation to the first extension thereon, a pivot pin journalled in said second extension with the axis thereof parallel with the axis of said shaft, a U-shaped member having a bight portion extending substantially parallel to said pivot pin and shaft and having the legs thereof supported on said pin, means for connecting one of said legs to the pin for pivotal movement of said member therewith, one of said legs being disposed in face adjacency with said second peripheral cheek extension, the other of said legs being extended from said pin in face adjacency with the other cheek, said ex tended leg having the extremity notched to receive said shaft, said shaft having means carried thereby and engageable with said leg extremity for locking the U- shaped member in said shaft engaged position of the extended leg, tongue means disposed within the swallow of the block and secured to said pin intermediate said second cheek extension and said extended leg, said tongue means having a tongue which moves into a position between the cheeks and in spaced adjacency with the peripheral surface of the sheave when said extended leg is moved to engage the shaft, and a swivel eye pivotally secured to said bight portion for pivotal movement about an axis disposed at right angles to and intersected with the axis of said pivot pin.

9. A self closing multiple sheave snatch block comprising a pair of sheaves, a common circular cheek for said sheaves having means including a centrally disposed shaft for supporting the sheaves for rotation thereon on opposite sides respectively of the cheek, said cheek having diametrically opposed peripheral extensions, a pair of circular cheeks disposed respectively outwardly of said sheaves and supported on said shaft, peripheral extensions on said outwardly disposed cheeks aligned with one of the peripheral extensions on said common cheek, means including spacers interposed between said last named extensions for maintaining said cheeks rigidly in predetermined spaced relation suflicient to provide free rotation of said sheaves therebetween, a pivot pin journalled in the other extension on said common cheek and having the pivot axis thereof extending parallel to the axis of said shaft, a U-shaped member having a bight portion parallel to said pivot axis and having legs supported by the extremities of said pin and extended respectively into face adjacency with said outwardly disposed cheeks, the extremities of said extended legs each having a notch for receiving said shaft, said shaft having means thereon engageable with said leg extremities for locking said U-shaped member in the shaft engaging position of the legs, means for securing the member to said pivot pin for pivotal movement therewith, a pair of tongue means secured to the pivot pin and disposed respectively between said last mentioned common cheek extension and the legs of said U-member and each having a tongue which moves into a position in spaced adjacency with the peripheral surface of one of the sheaves and between the cheeks individual thereto when the U-member is pivoted to engage the legs thereof with said shaft, and a swivel pivotally secured to said bight portion for pivotal movement about an axis at right angles to said axis of the pivot pin and intersected therewith.

References Cited in the file of this patent UNITED STATES PATENTS 402,208 Uren Apr. 30, 1889 1,753,084 Kappel Apr. 1, 1930 2,060,174 Campbell Nov. 10, 1936 2,262,328 McKissick Nov. 11, 1941 

